Photo by Friends of the High Line
The High Line's planting design is inspired by the self-seeded landscape that grew up between rail tracks after the trains stopped running in the 1980s. Today, the High Line includes more than 300 species of perennials, grasses, shrubs, and trees – each chosen for their hardiness, adaptability, diversity, and seasonal variation in color and texture. Some of the species that originally grew on the High Line's rail bed are reflected in the park landscape today.
This week we share one of our gardeners' current favorites with you.
In the bitter cold, blustery months of January and February, visiting an outdoor garden may not be on everyone's to-do list. However, for those willing to brave the elements on The High Line, they will be treated to a winter display of the prior season's structure, or "bones", left behind. One of the stand out species during this time is river birch, Betula nigra. This group of broad-leaf, deciduous woodies is one of very few species that thrive in the harsh tundra climate of the Northern Hemisphere. The 60 or so species of Betula vary mostly by bark color, but Betula nigra stands out as one of the most adaptable. Its heat hardiness allows it to be one of the most southern-prevalent of all birches. Its habitat ranges as far south as northern parts of Florida, and it grows naturally throughout thirty states in the eastern half of the United States.
Betula nigra is one of the largest in its genera, growing up to 50 feet by 35 feet, which makes it the largest of our native birches. It normally grows with a central leader and small-diameter, lateral branches. The light branch structure allows for a weeping effect during rain and snow events, adding to its already attractive form. Most notably it lacks the white bark associated with other birch species, but is distinguished by its shades of reddish, brown bark that peel off in papery curls. This provides great year-round interest, especially in the winter months when it contrasts with the white winter landscape.
Culturally, Betula nigra is the hardiest of all the Betula species. A common issue that most birches face and significantly suffer from is an infestation of the bronze birch borer, Agrilus anxius. The bronze birch borer is attracted by a chemical called rhododendrol, which is produced by a stressed birch, typically due to high summer temperatures. River birch is the only native species that does not produce this chemical, making it resistant to the pest. Another trait that makes it a hardy species is its ability to grow in very acidic soils, with a pH less than 6.5. Betula nigra also has the ability to grow in polluted stream bottoms with a pH as low as 2, where other hardwoods would not be able to do so. With its fast growth and extensive root system, it also provides erosion control along water banks and in steep topography.
These factors make Betula nigra a great addition to a garden or to a homeowner's landscape. Here at The High Line you'll find one example of its beautiful form in the Gansevoort Woodland, just south of Little West 12th Street. Although it was not originally slated to be a part of our diverse planting scheme, it made its way in–accidentally–amongst its cousin species, the grey birch. At a glance, young-age Betula bark color can be deceptively similar, making it easy to misidentify a particular species.
WHERE TO SEE THIS PLANT
You can find Betula nigra in the Gansevoort Woodland, just south of Little West 12th Street.
Our horticultural team counts on members and friends like you to help keep the High Line beautiful and thriving. Join our community of supporters who play an essential role in the High Line's most important gardening projects – become a member of Friends of the High Line today!